Machine tool for assembling and installing very small and lightweight parts

ABSTRACT

A machine-tool module for inserting and staking very small and lightweight contacts in a support member such as an electrical switch finger is disclosed and claimed. The device comprises a rotatable escapement element having a transporter adapted to receive a contact at an escapement receiving position from a first guide. The escapement element bearing the contact then rotates between the receiving position and an escapement delivery position to deliver the contact to a second guide. An impeller system urges the contact along the second guide to the contact installation point. A fluid pressure differential across the contact when the contact is in the guide impels the contact to move along the guide.

The present invention relates to punch press equipment and moreparticularly to a modular punch press station and its operation.

U.S. Pat. No. 5,218,756 describes and claims a modular punch pressdevice which is especially adapted to feed, guide and insert arivet-like electrical contact into a supporting metal piece. In thisdevice, when a punch pin hammer forces the contact against an opposinganvil, the contact stem is deformed and staked in and to the supportmetal piece.

The modular punch press device or station described in the '756 patentis especially useful for assembling and installing small, light-weightrivet-like electrical contacts in the longitudinally extended fingers ofan electrical finger contact switch. These contact switches, which arethemselves relatively small, are used in a myriad of applications suchas automobile electrical systems.

Some forms of these electrical contacts can be very small and light inweight. For example, some of these contacts handled by the equipmentembodying the disclosure and invention of the '756 patent weigh onlyabout 0.0001 pound; i.e. 9,900 of these contacts weigh only about 1pound. Typically, the head diameter of one of these contacts is about0.125 inch; the shank diameter is about half that, or about 0.062 inch.The head thickness may be from 0.021 inches to 0.035 inches, and theshank length may be from 0.031 inches to 0.070 inches.

Experience and experimentation have shown that there are lower limits tothe size and weight of the electrical contacts which can be reliably andrapidly handled by the equipment described and claimed in the '756patent. At present, when electrical contacts which are smaller andlighter than these lower limits are to be installed in electrical switchfingers or other support pieces, those contacts must be installed andsecured in and on the fingers by laborious, slow and expensive manualoperations.

It is accordingly the general object of this invention to provide punchpress equipment which will reliably, rapidly and inexpensively installextremely small, lightweight contacts in support members such as figuresfor electrical contact finger switches. Some of these contacts may beapproximately one-half the size and weight of the contacts describedabove. These extra-small contacts may each have a head diameter ofapproximately 0.062 inch; a shank diameter of 0.035 inch; a headthickness of 0.030 inch and a shank length of 0.050 inch. And thesecontacts are light in weight: approximately 114,000 of these contactscollectively weigh approximately 1 pound. These small, lightweightcontacts contemplated here are so small in size and so light in weightthat they cannot be effectively, reliably and rapidly handled bypreviously known automated punch press equipment.

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to thedrawings. Throughout the drawings, like reference numerals refer to likeparts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a preferred embodiment of the inventionand adjacent equipment.

FIG. 1A is an elevational view of an un-staked rivet-like contact.

FIG. 1B is a sectional view of a contact staked in and on a supportelement such as an electrical switch finger.

FIG. 2 is a top plan view of equipment embodying the invention.

FIG. 3 is an elevational view in partial section showing the equipmentand apparatus of FIG. 1. No escapement member cap is shown in thisfigure.

FIGS. 4 and 5 are a top plan view and an elevational view in partialsection, respectively, of a novel escapement mechanism and supportingapparatus showing the escapement mechanism in a contact deliveryconfiguration; i.e. in the configuration provided when the contact isbeing delivered from a first guide to the escapement.

FIG. 4A is a top plan view in partial section of an escapement elementand a contact element as they appear when the contact is beingtransported for installation in a support element such as an electricalswitch finger.

FIGS. 6 and 7 comprise a top plan view and an elevational view inpartial section, respectively, of the novel escapement mechanism andsupporting apparatus showing the escapement mechanism in a contacttransport configuration; i.e. in the configuration provided when thecontact is being held by the escapement element for movement anddelivery to a second guide.

FIG. 8 is a top plan view of the escapement mechanism and the associatedescapement rotating drive mechanism as they are configured when thecontact is in position to be transported to the second guide orinsertion track.

FIG. 8A is a top plan view similar to FIG. 8 but showing the contact andescapement mechanism as they are configured when the contact has beentransported and is aligned for delivery to the second guide or insertiontrack.

FIG. 9 is an elevational view of the mechanism shown in FIG. 8.

FIG. 10 is an elevational view of the escapement mechanism and anassociated ram cam mechanism when the escapement mechanism is located inits contact receiving position.

FIG. 11 is an elevational view similar to FIG. 10 but showing theescapement mechanism and associated ram cam mechanism when they arelocated in the contact delivery position.

FIG. 12 is a fragmentary top plan view showing the escapement mechanismwhen it is configured to receive a contact.

FIG. 13 is a fragmentary top plan view similar to FIG. 12 but showingthe escapement mechanism when it is configured to deliver a contact tothe second guide.

FIG. 14 is a top plan view showing the escapement mechanism when it isconfigured to receive a contact.

FIG. 15 is a top plan view similar to FIG. 14 but showing the escapementmechanism when it is configured to deliver a contact to the secondguide.

DETAILED DESCRIPTION

While the invention will be described in connection with a preferredembodiment, it will be understood that it is not intended to limit theinvention to this embodiment. On the contrary, it is intended to coverall alternatives, modifications and equivalents as may be includedwithin the spirit and scope of the invention as defined by the appendedclaims.

Turning more particularly to the drawings, and especially to FIGS. 1-3,an embodiment of a contact feed and installation station module 20 isillustrated as that station 20 may appear as part of a multi-stationpunch press and assembly machine 22 of known design. At other stations(not shown) preliminary forming and other operations can be performedupon, for example, a metal strip S. A feeding mechanism 24, which inthis preferred embodiment is a vibratory bin or reservoir feeder, ismounted to a support plate 26 to direct a series of contacts from thereservoir along a first, relatively short ramped guide 28. In thisparticular embodiment, the insertion pieces are rivet-like contacts 30each having a shank 31 and a relatively extended head 32. These contactsare relatively small, each having dimensions on the order of thedimensions described above. Preferably these small contacts 30 arecarried along the first guide 28 in a head-down, shank-up configurationas suggested in FIG. 1A. To this end, the first guide has across-sectional shape which will accommodate the contacts 30 only inthis configuration. The first guide 28 is inclined and/or can beprovided with a known vibratory motion so that the contacts 30 flow in acontinuous stream in single file from the reservoir 24 to a rotatableescapement mechanism 40 (FIG. 2) at an escapement receiving position 42.

In accordance with the invention and as illustrated in FIGS. 4-7, theescapement mechanism 40 includes a rotatable escapement element 44 whichis adapted to receive a contact 30 from the first guide 28 at theescapement receiving position in a transporter recess 46, as shown inFIG. 4A. The escapement mechanism 40 then causes the escapement element44 to rotate through approximately 90° from the contact receivingposition shown in FIGS. 4 and 5 to an escapement contact deliveryposition shown in FIGS. 6 and 7.

This rotatable motion of the escapement element 44 is provided by anescapement drive system. An embodiment of this escapement drive systemis shown in FIGS. 8-11, and parts of the drive system are suggested inFIGS. 12-15. The escape element 44 rotates about its center 50 by theaction of a connecting rod 52 which is journaled to the escapementelement 44 at an eccentric point 53. The connecting rod 52 is alsojournaled to a drive slide 54 at a pin-like bearing 55. As suggested inFIGS. 8-13 and elsewhere, this drive slide 54 is mounted within themodule 20 by conventional means for reciprocal motion. To accommodatethis arrangement of the slide 54, the escapement element 44, and theassociated parts, the drive slide 54 can be provided with a recess 56 assuggested in FIG. 8A.

Drive slide motion can be initiated by the action of a ram cam 60 movingin a downward direction so as to at least intermittently engage thedrive slide 54, as suggested in FIGS. 10 and 11. The drive slide 54 andthe ram cam 60 are provided with mating beveled surfaces 64, 65 so that,when the ram cam 60 descends as suggested in FIG. 11, the drive slide 54is pushed to the left into the position shown in FIG. 11. This driveslide motion causes corresponding rotation of the escapement element 44,but the motion of the ram cam 66 past the drive slide 54 permits amomentary halt or dwell to the escapement element rotational motion soas to permit delivery of the contact from the escapement element todownstream portions of the equipment, as described below. As the ram cam60 is withdrawn in an upward direction, the drive slide 54 is pushed tothe right by the action of a return spring 70 which is the leastpartially mounted within the drive slide 54, as suggested in FIGS. 10-13and elsewhere. In the illustrated embodiment, the ram cam 60 completelydisengages from the contact drive slide 54 as the ram cam moves throughthe upper part of its stroke, thereby leaving the drive slide 54immobile in its rightmost position as shown in FIG. 10, therebyproviding dwell time for the escapement 44 when the escape and 44 isreceiving a contact for subsequent transport.

When the escapement 44 has been rotated from its contact receivingposition shown in FIG. 12 to the escape of delivery position shown inFIG. 13, the contact is delivered to a second guide 80 by an impellersystem. In accordance with this aspect of the invention, the contact isimpelled to travel along this second guide 80 by a fluid pressuredifferential created across the contact. Here in the illustratedembodiment of the invention, this contact motion is compelled bycompressed air which is delivered from a known remote source (not shown)through a first series of fluid passages or conduits 82, 84. Theescapement element 44 is provided with one or more second passages 86which are arranged to be aligned in registry with a confronting end of afirst passage 82 when the escapement 44 is rotated into its contactdelivery position as shown in FIGS. 7 and 13. When the element 44 andair passages are so aligned, the contact is blown from the transportrecess 46 (FIG. 4A) into and along the second guide 80 to a contactinstallation point 100 (FIG. 3). As suggested in FIG. 2 and elsewhere,these fluid passages are out of registry with one another so as toobstruct fluid communication between the fluid source and the escapementelement transporter formation 46 when the escapement element 44 is notin its escapement delivery position.

It will be understood that the contact 30 so transported and deliveredto the contact installation point 100 is in a head-down, shank-upconfiguration (FIG. 3). When it arrives at the installation point 100,the contact is engaged by an anvil of known design located at arelatively lower position below the contact, and a ram of known designis positioned above the contact. During its downward stroke, the ramengages the free end of the contact shank at its upper end and deformsthat shank free into an enlarged head so as to secure the rivet-likecontact in the support piece S, as shown in FIG. 1B.

1. A device for inserting and staking a rivet-like contact into asupport piece, comprising, in combination, a first guide for carryingcontacts in single file fashion to an escapement receiving position, arotatable escapement mechanism adapted to receive a contact from thefirst guide at the escapement receiving position, to rotate between thereceiving position and an escapement delivery position, and to deliverthe contact at the delivery position to a second guide, and a secondguide for carrying a contact from the escapement delivery position to acontact installation point.
 2. A device according to claim 1 furtherincluding an impeller system for urging the contact along the secondguide from the escapement delivery position to the contact installationpoint.
 3. A device according to claim 2 further including a stakingmechanism for securing the contact into a support piece.
 4. A deviceaccording to claim 1 wherein said first guide comprises a track having across-sectional shape adapted to carry the contacts in a head-down,shank-up configuration.
 5. A mechanism according to claim 3 wherein thestaking mechanism includes an anvil member and a ram member each locatedat the installation point, the anvil being positioned to engage andsupport a contact head at a relatively lower location, and the ram beingpositioned to engage a free end of a contact shank at a relatively upperlocation and to deform that shank free end into an enlarged head so asto secure the rivet-like contact in the support piece.
 6. A deviceaccording to claim 1 wherein said escapement mechanism has an escapementelement mounted for reciprocal rotary motion between the escapementreceiving position and the escapement delivery position.
 7. A deviceaccording to claim 6 wherein said escapement element includes atransporter arranged to receive, engage and transport a contact from theescapement receiving position to the escapement delivery position.
 8. Adevice according to claim 6 further including an escapement drive slideand a connecting rod pivotally mounted to the escapement element and theescapement drive slide.
 9. A device according to claim 8 wherein saidmechanism includes a ram cam mounted for reciprocal motion, and whereinsaid escapement drive slide has a beveled cam surface adapted andpositioned for at least intermittent engagement by the ram cam.
 10. Adevice according to claim 8 further including a biased element forurging the drive slide through at least part of its reciprocal motion.11. A device according to claim 7 wherein said impeller system includesa number of fluid passages which are positioned so as to be in registrywith one another to provide fluid communication between a fluid sourceand said escapement element transporter when the escapement element isin its escapement delivery position, the fluid passages being out ofregistry with one another so as to obstruct fluid communication betweenthe fluid source and said escapement element transporter when theescapement element is not in its escapement delivery position.
 12. Adevice for inserting and staking a rivet-like contact into a supportpiece at an insertion point, comprising, in combination, a rotatableescapement element having a transporter adapted to receive a contact atan escapement receiving position, the escapement element being adaptedto rotate between the receiving position and an escapement deliveryposition, and to deliver the contact at the escapement delivery positionto a second guide, a guide for carrying a contact from the escapementdelivery position to a contact installation point, and an impellersystem for urging the contact along the guide from the escapementdelivery position to the contact installation point, the impeller systemincluding at least first and second fluid passages, the first and secondfluid passages being in fluid communication with one another and withthe escapement element transporter when the escapement element is in itsescapement delivery position so as to deliver a contact from theescapement element transporter to the insertion position.
 13. A deviceaccording to claim 12 further including a staking mechanism having ananvil member and a ram member each located at the contact installationpoint, the anvil member being positioned to engage and support a contacthead at a relatively lower location, and the ram being positioned toengage a free end of a contact shank at a relatively upper location andto deform that shank free end into an enlarged head so as to secure therivet-like contact in the support piece.
 14. A device according to claim13 further including an escapement drive slide and a connecting rodpivotally mounted to the escapement element and the escapement driveslide for driving the escapement element in an at least partiallyoscillatory motion.
 15. A device according to claim 14 wherein saidmechanism includes a ram cam mounted for reciprocal motion, and whereinsaid ram cam has a beveled cam surface adapted and positioned for atleast intermittent engagement by the drive slide.
 16. A device accordingto claim 15 wherein said mechanism includes a ram cam mounted forreciprocal motion, and wherein said escapement drive slide has a beveledcam surface adapted and positioned for at least intermittent engagementby the ram cam.
 17. A device according to claim 16 further including abiasing element for urging the drive slide through at least part of itsreciprocal motion.
 18. A method for inserting and staking a rivet-likecontact into a support piece, comprising the steps of: providing asingle contact to an escapement mechanism at an escapement receivingposition, rotating the escapement element and the provided contact fromthe escapement receiving position to an escapement delivery position,delivering the contact from the escapement mechanism to a guide,impelling the contact along the guide to a contact installation point,and staking the contact in a support piece.
 19. The method according toclaim 18 including the step of causing a fluid pressure differentialacross the contact when the contact is in the guide so as to impel thecontact to move along the guide to the contact installation point. 20.The method according to claim 18 further including the step of causing astaking ram member to move in oscillatory manner in synchronization withoscillatory rotational movement of the escapement member.